Application Of Heat Treatment Research Articles

Solvent-exchange-assisted activation of Cu-1,4-benzene dicarboxylate metal-organic framework for use as a bifunctional water splitting electrocatalyst

The activation of metal-organic frameworks (MOFs) to eliminate extra-coordinating and pore-filling solvent molecules is essential before using MOFs in catalysis applications. Herein, we developed a solvent-exchange-assisted technique to activate cathodically electrodeposited MOF containing Cu nodes and 1,4-benzene dicarboxylate (BDC) linkers, known as Cu(BDC). This method was initially executed by washing electrodeposited MOF film in ethanol and acetone, followed by soaking in dichloromethane and applying heat treatment at a low temperature to remove strongly coordinating N,N-dimethylformamide (DMF) molecules, thereby properly accessing a well-arranged mesoporous architecture with abundant active sites toward electrocatalysis. The emergence of open-state Cu centers through this safe activation method offers a catalyst with enhanced electrocatalytic performance that displays low overpotentials of only 212 mV and 341 mV at a current density of 10 mA.cm−2 toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Importantly, this study paves a way for developing low-cost methods for production and activation of MOFs for high efficient and stable alkaline water splitting.

Effects of Thermal Manipulation During the Second Half of Incubation on Embryo Physiology, Hatching Parameters, and Quality of Broiler Chickens in Tropical Climate of Togo

Chickens are sensitive to environmental challenges caused by temperature. The current study aimed to determine the effects of heat manipulation during embryonic development on the physiological responses of Goliath chickens. A total of 2000 hatching eggs from 48-week-old breeders were weighed, numbered, and randomly distributed equally into 4 incubators. Each incubator received 500 eggs (4 replicates of 125 eggs each). Eggs in two of the incubators were rotated hourly at a 45° angle and maintained at 37.8°C and 60% relative humidity (T0 groups). Between embryonic days (ED) 10 and 18 of incubation, the eggs from the other two incubators were heated to 38.5°C for 6 hours per day (T1 groups). The eggs were reweighed and candled, and viable eggs were moved to the hatching baskets at ED 18 of incubation. Hatching eggs were examined individually for hatching events every three hours during the final three days of incubation. On day 21, blood samples were collected from 12 chicks per group for hormonal and biochemical analyses. The evaluated blood parameters included Triiodothyronine (T3), T4 (thyroxine), cortisol, uric acid, lactate dehydrogenase, and total protein. At hatch, chicks were weighed and their quality (survival after hatching and performance standards) was evaluated. Data were collected on embryonic development, hatching window, hatching events, biochemical parameters, and hormonal concentrations. Results indicated that hatchability, chick’s weight, Tri-iodothyronine, and corticosterone were higher in the T1 group, compared to the control group. At hatch on day 21, the pipping muscle of chicks in the treated group (T1) was significantly heavier than that of the control group, while the embryonic mortality rate was significantly higher in the T0 group. In conclusion, applying heat treatment for 6 hours at 38.5°C from ED10-ED18 of embryogenesis increased significantly the hatching rate, the pipping muscle, and the chick’s weight in this study. Keywords: Embryonic development, Physiology, Slow-growing broiler, Thermal manipulation, Tropical climate

Evaluation of antinutrients, nutritional, and functional properties in sacha inchi (Plukenetia volubilis L) cake treated with hydrothermal processes

Applying heat treatments using an autoclave and hot air sterilization can alter the proximal composition, technofunctional properties, and antinutrient content of Sacha inchi (P. volubilis) oil press cake. The autoclave and hot air treatments significantly reduced antinutrients compared to the control. The samples treated with autoclave and hot air sterilization exhibited a significant decrease in alkaloids, nitrates, tannins, saponins, and trypsin inhibitors compared to the control sample. However, the 20-min autoclave treatment did not significantly reduce the saponin antinutrients. Phytic acid significantly decreased in the 30-min hot air sample and autoclave 20-min/hot air treatments, respectively. On the other hand, the levels of antinutrients oxalate and thiocyanates did not significant difference between the control and hot air treatments. However, the autoclave treatment resulted in a significant reduction in oxalates. The study found that hydrotreatments at temperatures of 121 °C with humid heat - autoclave showed significant differences in protein content compared to the control sample, with content of 37.75 + 0.2 g/100g. Samples treated with an autoclave for 10, 20, and 30 min showed values of protein 53.19 + 0.28, 66.08 + 2.6, and 70.12 + 0.48 g/100g, respectively. Meanwhile, samples treated with dry heat showed significant differences with the sample treated for 10 min having a protein content of 60.21 + 6.80 g/100g. The techno-functional properties analyzed in the study demonstrated a significant decrease in hydrating properties such as water holding capacity (WHC), water retention capacity (WRC), and swelling capacity (SC) due to changes in the solubility of proteins for the two treatments and the oil holding capacity (OHC) property showed a significant increase. Finally, water's presence during hydrothermal treatments significantly reduces antinutrients, providing guidance for analyzing other study variables.

Understanding the impact of Li2CO3 distribution within solid electrolyte interphases on lithium metal via thermal conditioning

The formation of a solid electrolyte interphase (SEI) is crucial for the performance and safety of Li metal batteries (LMBs). The SEI consists of various compounds that are assumed to prevent electrolyte decomposition and dendrite growth. Among these constituents, Li2CO3 has a contentious position; some studies stated that it is a beneficial component, whereas others viewed it as an impurity. This study investigated the influence of strategic heat treatments on the distribution of Li2CO3 formed in the SEI of Li metal. These treatments affect the cycling performance of Li/LiCoO2 cells, as evidenced by the differences in cycle life and capacity. In particular, the study showed that samples heat-treated at higher temperatures generally exhibited enhanced performances, illustrating the impact of heat treatment on SEI quality. The quality of the SEI, which depends on the Li2CO3 formation model (solid electrolyte interface layer or a solid polymer electrolyte layer), varies depending on the applied heat treatment. The samples heat-treated at 120 °C followed the solid polymer electrolyte layer model, resulting in the mosaic-style formation of Li2CO3. This intricate pattern provides superior mechanical stability compared with that of a plain layer-type structure and can be used to develop potential strategies for the enhancement of the cycling stability and overall longevity of LMBs.

Mixing oat proteins with lentil or faba bean proteins: How is the techno-functional behavior of the different protein systems affected by heat treatments?

Despite the growing market for plant-based products, rarely a single plant protein source manages to provide all the essential amino acids in a balanced way. Mixed protein systems combining proteins from more than one plant source may be useful to overcome this drawback. However, the mixture of proteins from different plant sources may impact the technological performance of the system. In this context, the influence of heat treatments of 75 and 95 °C for 15 min at neutral pH on the colloidal and the techno-functional properties of mixtures of protein isolates from lentil and oat (LO) and from faba bean and oat (FO) were investigated. The applied heat treatments induced subtle changes in the colloidal properties of the different systems. It was evidenced by size exclusion chromatography that oat proteins were more prone to heat induced changes than lentil or faba bean proteins. Regarding the techno-functional properties, mixing the proteins from the different sources had an antagonistic effect on foamability. On the other hand, an additive effect was observed for emulsifying capacities, with legume proteins displaying values between 93 and 100%, oat proteins close to 65%, and mixed systems between 78 and 93 %. Vicilin (7S) and β-basic subunits of legumin (11S) from lentil and faba bean, and oat 12S globulin were the main protein fractions stabilizing the interface of the obtained emulsions. The proteins from both sources coexisted at the interface of the emulsions stabilized by the mixed systems. The microstructure of the thermo-induced gels was dictated by oat proteins. However, the different legumes played a determining role in the critical gelling concentration measured (8 % w/w and 11.5 % w/w respectively for LO and FO). Mixing oat proteins with lentil or faba bean proteins allows modulating the techno-functional performance of the systems, thus represents an opportunity for innovative applications.

Numerical modeling of shear band effect on Goss grain recrystallization in electrical steels: Crystal plasticity finite element and phase field modeling

This study investigates the effect of shear band evolution on the nucleation of Goss {110}<001> texture during the primary recrystallization of 3.24 wt% Si grain-oriented electrical steel. Nucleation at the early stage of primary recrystallization of the steel is explored both experimentally and numerically. The experimental approach involves cold rolling the steel specimens to obtain a thickness reduction ratio of 76 % and then applying heat treatment to them at 600 °C for less than 1 min. The numerical simulation employes crystal plasticity (CP) finite element model (FEM) to simulate the plastic deformation induced by the dislocation slips on predefined slip systems and non-crystallographic shear bands during cold rolling. Based on the CPFEM results, the generalized strain energy release maximization (GSERM) model is used to predict the preferential orientation probability of recrystallized nuclei for the steel by considering shear band formation. Subsequently, the microstructure evolution during the early stage of primary recrystallization of the steel is simulated using the phase field model (PFM). The developed CP model successfully predicted shear band activation and evolution in the γ-fibers centered on the {111}<112> texture component. The model also demonstrated that shear bands would be the preferred nucleation sites at the early stage of primary recrystallization because of their high stored energy. Moreover, by coupling with the GSERM model, the PFM could reproduce the nucleation of Goss grains at the beginning of primary recrystallization in shear bands.

Analysis of the Mechanical and Physical Behaviors of 3D-Printed PEEK Structures under Different Parameters

In this study, the mechanical and physical properties of polyetheretherketone (PEEK) material produced through three-dimensional (3D) printing under different production parameters were investigated. For this purpose, the results obtained by applying heat treatment to the produced samples were examined. Comparisons based on mechanical properties were supported by 3D surface profiles and XRD analyses. According to the obtained results, low nozzle diameter and high printing temperature led to an increase of up to 8% in the elastic modulus and up to 33% in tensile strength of the samples. The heat treatment applied in the study increased tensile strength by up to 8% and elastic modulus by up to 9% in samples produced with a low-diameter nozzle. In conclusion, this study aims to provide a dataset for 3D PEEK designs, intending to enhance the performance of PEEK materials that can be used in medical and industrial applications.

Physicochemical Properties of Different Melon Seed Oils Dried at Different Temperatures

In this study, the effect of the drying process on the quality of oils obtained from different melon seeds was investigated. The seeds of two different melon varieties (Kırkağaç, Hasanbey) were separated and dried in the oven at different temperatures (30, 50 and 70 °C). Moisture, 1000 grain weight, width, length, thickness, oil yield, free fatty acidity, peroxide value, color values (L*, a*, b*), and total phenolic substance amounts and fatty acid composition were examined. The average of initial moisture values was 6.42% and 5.48%. The drying process was carried out until the moisture rate of melon seeds reached 1%. The average of most values of the cores varied from 4.55-5.16 mm, length 12.82-13.18 mm, thickness 1.21-1.38 mm and 1000 grain weights varied from 52.40-45.70 g. The amount of total phenolic substances of Kırkağaç melon seed oil was found in the range of 584-691 mg GAE /kg, and Hasanbey melon seed oil in the range 780-840 mgGAE / kg. The amount of total phenolic substance decreased with the applied heat treatment. The peroxide values of the oil obtained from Kırkağaç and Hasanbey beans in terms of meqO2 / kg varied between 6.9-8.4 and 7.2-9.1, respectively. The highest peroxide value was observed in oil obtained from beans dried at 70°C in both varieties. It has been observed that oleic and palmitic acids are also followed by linoleic acid compared to fatty acid composition compared to other fatty acids. According to the results obtained, it was determined that the most effective drying temperature was 50°C in terms of efficiency and quality.

Carbon molecular sieve electrodes with intrinsic microporosity for efficient capacitive deionization

Capacitive deionization (CDI), apromisingprocessfor desalinatinglow-salinity water, is currently characterized by the prevalent use of activated carbon (AC) electrodes that exhibit somewhat suboptimal performance. One potential method for increasing the electrosorption capacity of an electrode involves boosting its porosity and conductivity by using conductive polymers or applying heat treatment to porous polymers. This study examines the performance of the capacitive deionization (CDI) process using a range of highly porous carbon molecular sieve (CMS) electrodes. These electrodes are derived from intrinsically microporous polyimide 4,4′-(hexa-fluoroisopropylidene) diphthalic-anhydride (6FDA)-3,3′ dimethyl-naphthidine (DMN) (6FDA-DMN) and prepared at temperatures of 600, 800, and 1000 °C. The electrodes that were produced exhibited a high Brunauer-Emmett-Teller (BET) surface area ranging from 574 to 729 m2g−1. Additionally, they displayed a symmetric cyclic voltammetry (CV) plot with a specific capacitance ranging from 17.75 to 67.91 Fg−1 at a scan rate of 5 mVs−1. The charge transfer resistance (Rct) values for the 6FDA-DMN-based CMS P1, P2, and P3 electrodes were measured to be 9.7 Ω, 1.2 Ω, and 0.9 Ω, respectively, in a 1 M NaCl solution. The CMS electrode, synthesized at a temperature of 800 °C (P2), exhibits exceptional electrosorption capabilities in a saline solution with a concentration of 600 mgL−1. It displays a remarkable capacity of 36.9 mgg−1 and a rate of 2 mgg−1min−1, surpassing the performance of activated carbons (ACs). This research establishes a pathway for optimizing the characteristics and performance of electrodes by thermal treatment. This research demonstrates for the first time the effect of thermal annealing on the CDI performance of CMS materials, which will aid in developing electrode materials for large-scale water desalination.

Influence of Imposed Strain on Weldability of Dievar Alloy.

The presented work is focused on the influence of imposed strain on the weldability of Dievar alloy. Two mechanisms affecting the microstructure and thus imparting changes in the mechanical properties were applied-heat treatment (hardening and tempering), and rotary swaging. The processed workpieces were further subjected to welding with various welding currents. In order to characterize the effects of welding on the microstructure, especially in the heat-affected zone, and determine material stability under elevated temperatures, samples for uniaxial hot compression testing at temperatures from 600 to 900 °C, optical and scanning electron microscopy, and microhardness testing were taken. The testing revealed that, although the rotary swaged and heat-treated samples featured comparable microhardness, the strength of the swaged material was approximately twice as high as that of the heat-treated one-specifically 1350 MPa. Furthermore, it was found that the rotary swaged sample exhibited favorable welding behavior when compared to the heat-treated one, when the higher welding current was applied.

Increasing Energy Efficiency by Optimizing Heat Treatment Parameters for High-Alloyed Tool Steels

AbstractIn the paper industry, machine circular knives are used in the cutting process to provide industrial quality cuts on a variety of products. In the production of paper rolls, they cut the long-rolled paper products into commercial sizes. For this application, the high-alloyed ledeburitic cold work tool steel, DIN EN 1.2379 (X153CrMoV12; AISI D2), in the secondary hardened heat-treated condition has become the widely used industry solution. However, its heat treatment is a very energy-intensive production process. It consists of a quenching from an austenitizing temperature above 1050 °C, followed by three high-temperature tempering steps of more than 500 °C. In the study, the heat treatment process was optimized for energy efficiency, resulting in superior material properties with lower energy consumption. The most promising low energy heat treatment developed in the laboratory was reproduced in the industrial scale, and the required energy consumption was quantified. Subsequently, the resulting properties of the tools such as hardness, wear resistance and fracture toughness were determined. The energy production costs and mechanical properties of the tool steel were evaluated in comparison to conventional production methods. The newly applied heat treatment condition showed very promising and positive results in all analyzed parameters.

How thermal treatment affects the chemical composition and the physical, mechanical and swelling properties of Scots pine juvenile and mature wood

High variations in juvenile wood properties in the radial direction and its worse performance than mature wood make it less suitable for some applications and often treated as waste material. This study aimed to assess how thermal modification affects the chemical composition and the physical, mechanical and swelling properties of Scots pine juvenile and mature wood. An additional goal was to evaluate if the modification can equalise the differences in selected properties of juvenile wood to those of mature wood so that from waste material, juvenile wood can become a fully-fledged raw material for various industrial applications. Thermal treatment at 220 °C influenced wood chemical composition, degrading mainly hemicelluloses but also affecting cellulose and lignin, which resulted in a reduction of hydroxyls and carbonyl/carboxyl groups. These changes were more pronounced for mature than juvenile wood. It reduced mass loss and swelling rate, and increased swelling pressure in the tangential and radial directions to a higher degree for juvenile than mature wood. Changes in mechanical properties in compression were statistically significant only for mature wood, while wood hardness remained unaffected. Although the applied heat treatment improved the performance of juvenile wood by reducing its swelling rate, it did not equalise the examined properties between juvenile and mature wood. Since higher juvenile wood proportion is expected in the wood supply from the future intensively managed forests, there is still a need to find suitable modification methods or better processing techniques so that instead of being thrown away as waste, it could be used broadly in various industrial applications.

Effect of roasting on the oil content, bioactive components, fatty acid composition and mineral content of purslane seeds

SummaryIn this study, the effect of microwave on oil contents, bioactive components, antioxidant activity, polyphenols, tocopherols, fatty acid compositions and nutrients of purslane seeds was investigated. The moisture amount of the purslane seeds decreased significantly, while the oil and bioactive properties of the seeds increased compared to the control. Raw (control) and purslane seeds roasted in microwave contained 24.72 and 26.27 mg/100 g gallic acid, 34.12 and 38.30 mg/100 g 3,4‐dihydroxybenzoic acid, 111.57 and 118.55 mg/100 g catechin, 8.70 and 3.46 caffeic acid, 5.95 and 5.09 mg/100 g syringic acid, 18.73 and 8.34 mg/100 g rutin and 3.07 and 2.26 mg/100 g quercetin, respectively. Stearic, linoleic, arachidic, linolenic, behenic and erucic acid results of the oils of raw and purslane seeds roasted in microwave were partially increased compared to raw seed oil. The applied heat treatment had a positive effect on the tocopherol results of the purslane seed oils, and the tocopherol contents of the oils obtained from the roasted seeds increased compared to the control. In general, the protein and mineral values of heat‐treated purslane seeds increased (except Ca, Fe and Mn).

Structural, optical, and magnetic characterization of Er-doped In2O3 nanoparticles

(In1-xErx)2O3 nanoparticles were synthesized by lyophilization of an aqueous solution of indium and erbium acetates and then applying heat treatments. These nanoparticles were characterized regarding their structural, optical, and magnetic properties over a temperature range of 2–300 K. For x ≤ 0.04, all samples were monophasic, crystallized with cubic structure (Ia-3 space group), and characterized by oxygen vacancies. Er doping reduced the crystallite size and increased the lattice strain. However, no change in energy bandgap was observed after erbium dilution in the oxide matrix. The doped samples were paramagnetic over the entire temperature range, but at low temperatures paramagnetism coexisted with a ferromagnetic phase. The ferromagnetism was attributed to the presence of magnetic polarons acting as mediators of the coupling between the Er3+ ions. The low-temperature segments of the magnetization curves, i.e., M(T< 20 K), were successfully fitted based on the Bound Magnetic Polaron model.

Structure and mechanical properties of PR-03N18K9M5TYu steel grade fabricated by selective laser melting and post-processing

We fabricate samples of PR-03N18K9M5TYu steel (equivalent to ChS4) using selective laser melting (SLM) in a nitrogen atmosphere. Our research focused on the influence of hot isostatic pressing (HIP) combined with heat treatment (HT), specifically hardening and aging, on the steel's structure and its physical and mechanical properties (σucs, σys, δ, ψ). Through tensile testing, we evaluated the impact of post-processing treatments (HIP followed by HT) on the material's strength. We also assessed how different post-processing protocols affected residual porosity. Our findings indicate that samples exhibiting the highest strength and plastic properties correspond to those with the least structural defects and minimal residual porosity. In-depth microstructural analysis revealed that the optimal structure–a fine-grained, homogeneous configuration–is achieved via the combined application of SLM, HIP, and subsequent HT. The improvement in mechanical properties can be primarily attributed to the dispersed hardening effect, which is a consequence of the precipitation of the superfluous Ni3Ti phase. Fractographic examination revealed that the post-processing leads to a ductile and dimple fracture, occurring through mechanisms of shearing and detachment, giving rise to mixed-type fractures. The samples that displayed superior mechanical properties were characterized by a homogenous ductile intergranular fracture surface with clear evidence of plastic deformation. We measured the hardness (Н), modulus of elasticity (Е), and elastic recovery via indentation methods. The post-processing treatments notably enhanced material hardness and elastic modulus, with an increase from H = 4.6 GPa and E = 194 GPa in the sample post-HIP to H = 8.5 GPa and E = 256 GPa following HIP coupled with hardening and aging.

Optimization of a tunable process for rapid production of calcium phosphate microparticles using a droplet-based microfluidic platform.

Calcium phosphate (CaP) biomaterials are amongst the most widely used synthetic bone graft substitutes, owing to their chemical similarities to the mineral part of bone matrix and off-the-shelf availability. However, their ability to regenerate bone in critical-sized bone defects has remained inferior to the gold standard autologous bone. Hence, there is a need for methods that can be employed to efficiently produce CaPs with different properties, enabling the screening and consequent fine-tuning of the properties of CaPs towards effective bone regeneration. To this end, we propose the use of droplet microfluidics for rapid production of a variety of CaP microparticles. Particularly, this study aims to optimize the steps of a droplet microfluidic-based production process, including droplet generation, in-droplet CaP synthesis, purification and sintering, in order to obtain a library of CaP microparticles with fine-tuned properties. The results showed that size-controlled, monodisperse water-in-oil microdroplets containing calcium- and phosphate-rich solutions can be produced using a flow-focusing droplet-generator microfluidic chip. We optimized synthesis protocols based on in-droplet mineralization to obtain a range of CaP microparticles without and with inorganic additives. This was achieved by adjusting synthesis parameters, such as precursor concentration, pH value, and aging time, and applying heat treatment. In addition, our results indicated that the synthesis and fabrication parameters of CaPs in this method can alter the microstructure and the degradation behavior of CaPs. Overall, the results highlight the potential of the droplet microfluidic platform for engineering CaP microparticle biomaterials with fine-tuned properties.

Effect of heat treatment on functionally graded 304L stainless steel to Inconel 625 fabricated by directed energy deposition

Defining appropriate heat treatments for compositionally functionally graded materials (FGMs) is challenging due to varying processing conditions in terminal alloys and gradient regions. Therefore, it is critical to investigate the impact of potential heat treatments on phase transformations and the resulting mechanical properties along the entire compositional path. In the present study, we applied heat treatments at 700 °C, 900 °C, and 1150 °C on a stainless steel 304L (SS304L) to Inconel 625 (IN625) FGM fabricated using directed energy deposition (DED) additive manufacturing (AM). The microstructure and hardness, as a function of layer-wise composition and applied heat treatment, were characterized. The applicability of computational methods previously developed by the team to predict experimentally observed phases by the hybrid Scheil-equilibrium approach was evaluated. This approach improves the accuracy of predicting phases formed after heat treatment compared to equilibrium thermodynamic calculations using the overall layer compositions and provides a simple pathway to assist in designing heat treatment for FGMs.

Energy Storage Performance of Electrode Materials Derived from Manganese Metal-Organic Frameworks.

Metal-organic frameworks (MOFs) are porous materials assembled using metal and organic linkers, showing a high specific surface area and a tunable pore size. Large portions of metal open sites in MOFs can be exposed to electrolyte ions, meaning they have high potential to be used as electrode materials in energy storage devices such as supercapacitors. Also, they can be easily converted into porous metal oxides by heat treatment. In this study, we obtained high energy storage performance by preparing electrode materials through applying heat treatment to manganese MOFs (Mn-MOFs) under air. The chemical and structural properties of synthesized and thermally treated Mn-MOFs were measured by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The surface area and porosity were investigated by nitrogen adsorption/desorption isotherms. The electrochemical properties were studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) using a three-electrode cell. It was found that Mn-MOF electrodes that underwent heat treatment at 400 °C under air consisted of Mn2O3 with high specific surface area and porosity. They also showed a superior specific capacitance of 214.0 F g-1 and an energy density value of 29.7 Wh kg-1 (at 0.1 A g-1) compared to non-treated Mn-MOFs.

Optimized intermediate layer formation and electroless plating methods to obtain supported dense Pd surfaces.

Dense metallic membranes, especially Pd and Pd alloys, have been intensely investigated to provide an alternative and economical way to obtain H2 with ultrahigh purity. To overcome the high cost of Pd, composite membrane structures that comprise a thin layer of Pd are utilized. However, it is a challenge to obtain a thin, dense, and uniform Pd layer on the support materials. This study investigates the parametric analysis of γ-Al2O3 interlayer formation and the electroless Pd plating (Pd ELP) procedures on α-Al2O3 supports with the aim to achieve a thin, uniform Pd surface without annealing. Adjustments in PEG/PVA concentration, dipping time, and heat treatment enabled creating a thin γ-Al2O3 interlayer on α-Al2O3, minimizing pore size and density. Hydrazine concentration, heat treatment, and bath temperature were adjusted to optimize Pd ELP to achieve maximum yield from the plating bath and a dense, uniform surface without annealing. Pd/γ-Al2O3/α-Al2O3 structures were analyzed using scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis to observe the impact of varied parameters on surface structures. Optimized sample was compared to an annealed Pd/α-Al2O3 prepared in accordance with literature methods and a Pd/graphite/α-Al2O3 sample to validate the use of optimized ELP procedure and the γ-Al2O3 interlayer. Results show that a dense and uniform 13 μm Pd coating was achieved on a γ-Al2O3-coated α-Al2O3 support without annealing, using three fresh ELP baths. This was done using sequential hydrazine addition with a decreased concentration (1 M) into the ELP baths at 30 °C, and applying heat treatment at 120 °C between each fresh ELP bath.

Effect of microwave and oven roasting on chemical composition, bioactive properties, phenolic compounds and fatty acid compositions of sunflower seed and oils

AbstractIn this study, the effects of microwave (540, 720 and 900 W) and oven (120, 150 and 230°C) roasting techniques on the total phenolics, flavonoids, antioxidant capacity, polyphenolic and fatty acid results of sunflower seed and oils were investigated. Total phenol (except oven 150°C), flavonoid (except oven 120°C) contents and antioxidant activity values of sunflower seeds and oils subjected to oven and microwave heat treatment decreased compared to the control. Total phenolic, total flavonoids and antioxidant activities were higher in MRS oil than ORS oil. Individual phenolic constituent in both seed and oil samples from ORS and MRS showed significant (p &lt; 0.05) changes to the control (non‐roasted seed and its oil). A general increase in the phenolic components of seeds and oils was observed with oven and microwave roasting compared to the control. Oleic acid values (%) of the oil extracted from seeds roasted in oven and microwave systems were recorded to be between 23.76 (120°C) and 29.41% (150°C) to 24.32 (540 W) and 26.10% (720 W), respectively. Linoleic acid values of the oils obtained from seeds roasted in oven and microwave systems varied to be between 57.01 (150°C) and 65.89% (120°C) to 60.70 (720 W) and 65.26% (540 W), respectively. As a result of the applied heat treatment, while the linoleic acid values of the oil samples decreased, an increase was observed in the palmitic, stearic and oleic acid values of the oil.